An emulsion is defined as a fine dispersion of minute droplets of a first liquid in a second liquid in which the first liquid is not soluble or miscible. The emulsion can occur by vigorous mixing or shaking of the liquid mixture. A liquid lens (such as those produced by Optilux of Santa Barbara, Calif.) is created by enclosing two fluids with an engineered index of refraction difference within a housing. The housing incorporates electrodes which manipulate the shape of the lens based on the principles of electro-wetting. In the case of a liquid lens, an emulsion of the fluids in undesirable as it will negatively impact the optical performance of the lens. This can occur if the lens is subject to shock loads, such as caused by an impact due to dropping the device.
Methods by which an emulsion of two fluids may be “demulsified” or separated back into its two fluid constituents are known in fields such as the oil/gas industry. For example, a centrifuge can be used to separate the two fluids based on differences in their density. Another prior art method to separate an emulsion is to use chemicals that affect the surface tension of the fluids. Yet another method involves using electric fields to induce coalescence of the droplets of one fluid. However, there is no known prior art that specifically addresses the problem of an emulsion in a liquid lens cavity, and in particular an emulsion caused by severe shock loading of a liquid lens device including such a cavity.
The need therefore exists for methods and systems specifically tailored to clear or remove an emulsion from the field of view of a liquid lens. Ideally the clearing would occur very quickly (in less than 10 seconds, for example) without the need for deliberate user input or the involvement of devices external to the liquid lens system. The clearing could occur automatically during power up, or may be initiated in response to a signal from a sensor.